The present invention relates to wireless data communication. More particularly, the present invention relates to a novel and improved method and apparatus for scheduling packet data transmissions in a wireless communication system.
In a wireless communication system, a base station communicates with multiple mobile users. Wireless communications may include low delay data communications, such as voice or video transmissions, or high data rate communications, such as packetized data transmissions. U.S. patent application Ser. No. 08/963,386, entitled xe2x80x9cMETHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,xe2x80x9d filed Nov. 3, 1997 describes high rate packet data transmissions, and hereby expressly incorporated by reference.
Packet data transmissions are not required to be low latency transmissions, and therefore allow the base station flexibility in scheduling mobile user transmissions within a system. Once scheduled, the base station may transmit data to as little as a single mobile user during a given time period. In general, scheduling of packet data mobile users in a system has two goals. The first goal is to optimize the utilization of each channel. The second goal is to allocate transmissions to mobile users fairly. The two goals sometimes compete. For example, channel quality conditions and the amount of pending data for a given user may result in excessive time allocations to that user particularly at the expense of other users.
There is a need, therefore, for a fair method for scheduling packet data transmissions to mobile users that is channel-sensitive.
The disclosed embodiments provide a novel and improved method for scheduling packet data transmissions in a wireless communication system. In one aspect, in a wireless communication system adapted for packet data transmissions, a method includes receiving rate request indicators for a plurality of mobile stations, calculating priority function values for the plurality of mobile stations in response to the rate request indicators, and scheduling transmissions to the mobile stations according to the priority function value.
According to another aspect, a wireless apparatus includes a priority factor calculation unit adapted to receive data rate requests from mobile stations and generate power factor values in response, and a scheduling unit coupled to the priority factor calculation unit, the scheduling unit adapted to schedule data transmissions.
According to still another aspect, a method for scheduling packet data transactions in a wireless communication system includes determining a pool of users, calculating a priority function of at least a portion of the pool of users, scheduling a first set of users having pending data transactions from the portion of the pool of users, receiving rate request indicators from the portion of the pool of users, and updating priority functions of the first set of users in response to the rate request indicators.